hi. I have a jetboat and have recently upgraded to 3.8 vr engine. goes like stink and very powerful although there is one (or more) problem(s). the boat goes really well nice engine note brilliant power and all that but when the engine gets warmer and after running for a while I park the boat up and it wont restart. the only way for it to restart is to open the engine bay and let it cool down for a half hour. while it wont start the fuel pump will go at the flick of a switch but still no firing. once it has cooled down the engine starts first pop and your away again. I have installed these engines in two other boats and they run fine but mine not so well... today we took it to the lake and one of the guys whose boat I installed a engine into came as well. they brought their great running holden commodore car (also vr) and we began to swap over parts, we exchanged ignition coils and dfi module unit, computer and also map sensor. Once exchanged the car ran well but the boat still wouldn't start ie the problem persists. Our conclusion is that perhaps my cooling system is not up to standards with the engine. this is the only differentiation between my boat and the two others. however I could do with some help before spending more money on something that may not work. thanks
Welcome to the club buddy!! Sounds as though the crank angle sensor is giving up. Just as a quick test when the engine is hot and will not restart pour some water over the sensor to cool it off and try restarting. The crank angle sensor is located behind the harmonic balancer on the left hand side of the engine (right hand side looking from the front. Let us know how you go with that buddy and we will go from there. Cheers
What's the difference between understeer and oversteer? Understeer is when the driver is scared. Oversteer is when the passenger is scared.
thanks for the info mate we will try your remedy when we next get the chance, but we've been looking through the workshop manual and reckon it could also be the oil sensor, because we have a manual oil gauge and the holdens have a computerised? gauge apparently this can retard the injectors and efi to stop them from working. the other two boats have the computerised? or electric gauges. we will try both ideas and hopefully we will get the reliability that youd expect from these engines. Thanks
Thanks for the help buddy we done what you said and it actually worked. do you recommend we buy another sensor or is it something causing the sensor to go off. im Forever in your debt mate forever in your debt
Deffinately replace sensor is on it's way out. If I remember correctly you can get them for about 150 - 200 last time I bought one. No debt owed here buddy we are here to help and share!! Cheers
What's the difference between understeer and oversteer? Understeer is when the driver is scared. Oversteer is when the passenger is scared.
I have a VN in my jet boat in nz. I have replaced the crank sensor about thre times in 100 hours. But since then I have had a major problem (backfiring at over 3000rpm) Tried everything ,replaced coolant sensor ,coilpack to a round set,part of the wiring loom, inlet manifold gasket and rev counter. Without driveshaft connected it now seems to run fine. I also made a heat exchanger for the fuel line as the fuel in the tank gets too hot for injection. Going for a blat on the weekend so will test it outand let you know
vr 3.8 commodore in jetboat
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Posted - 03 Jan 2012 : 5:18:27 PM
